[Ditter]

The WMD/chemicals were all dumped into the Euphrates river at the beginning of the war. That why the barrels were empty. Remember?

[CyberAnt]

"chemicals were all dumped"

Well ... I just don't believe it was "all" dumped. There may have been some, but from the store they were supposed to have, what they found in the river would only have been the tip of the iceberg.